In recent years, various forms of information recording media has been used for recording digital data. Among others, write-once optical discs are gaining wide use although data can be recorded only once, since the cost thereof is inexpensive.
Examples of such optical discs include CD-R discs and DVD-R discs. Several methods for incrementally recording data on CD-R discs or DVD-R discs have been proposed (see, for example, U.S. Pat. No. 5,666,531). The methods for incrementally recording data may be, for example, a VAT (Virtual Allocation Table) method, or a multiborder (multisession) method.
Operations for recording/reproducing digital data on/from DVD-R discs using the VAT method or multiborder method will be described.
First, incrementally recording method using VAT will be described below with reference to the drawings. Herein, an operation for recording a file and directory tree structure shown in FIG. 12 on an information recording medium and a data structure which is formed as a result thereof when an example of the recording information medium is a DVD-R disc will be described in steps.
First, a format process will be described with reference to FIG. 13. FIG. 13 shows data immediately after a format process which is on a DVD-R disc, an example of a conventional information recording medium 10100.
A DVD-R disc is an information recording medium defined by the DVD-R physical specification.
Further, files are recorded by using a volume file structure defined by the DVD-R file system specification. The DVD-R file system specification conforms to the ISO/IEC 13346 standard or the UDF (Universal Disk Format) specification. The description will be made below using the structure defined by the UDF specification.
As shown in FIG. 13, a data area included on the information recording medium 10100 includes a lead-in area 10101 and a volume space 10109.
The volume space 10109 includes a volume structure area 10410, a file structure/file area 10420, and a VAT (Virtual Allocation Table) structure area 10430.
In the volume structure area 10410, a volume structure defined by the UDF specification is to be recorded. In detail, the volume structure area 10410 includes an NSR descriptor, a primary volume descriptor, an implementation use volume descriptor, a partition descriptor, a logical volume descriptor, an unallocated space descriptor, a terminating descriptor, a logical volume integrity descriptor, an anchor volume descriptor pointer, and the like.
The file structure/file area 10420 includes a file set descriptor 10421, which will be an origin of a directory tree in a partition space, and an FE (ROOT) 10422, which is a file entry of a ROOT directory file.
The file entry (hereinafter, referred to as FE) has a data structure defined by the UDF specification for managing the position and the size of the files to be recorded in the volume space. Herein, in order to simplify the description, the ROOT directory file is assumed to be recorded in the FE (ROOT) 10422.
In the VAT structure area 10430, a VAT 10431 and a VAT ICB 10432 are recorded. The VAT is a data structure defined by the UDF specification with the purpose of simplifying the updating process of the file structure in the write-once recording medium.
When the VAT is used, a recording position of the file structure data such as FE in the volume space is specified using virtual address in a virtual address space.
VAT holds a correspondence between a logical address, which is a recording position in a logical address space on the information recording medium, and the virtual address.
With such a structure, data can be rewritten virtually even in an information recording medium which is not rewritable, such as a DVD-R disc.
The recording position of the VAT on the information recording medium is specified by VAT ICB allocated to a last sector of an area on which data is recorded on the information recording medium.
Further, the lead-in area 10101 includes a physical format information area 10104. The physical format information is provided for recording management information of various areas allocated on the information recording medium 10100. The management information may be, for example, address information of a border-out area or the like. Immediately after the format process, only an area of the physical format information area 10104 is recorded, and data is not recorded yet in the area.
Next, with reference to FIG. 14, a procedure for recording directory (Dir-A) and data file (File-a) of the file and directory structure shown in FIG. 12 will be described.
When a process of recording the directory (Dir-A) and data file (File-a) to the information recording medium 10100 as shown in FIG. 13 is performed, a data file (File-a) 10501, a FE (File-a) 10502, a FE (Dir-A) 10503, and FE (ROOT) 10504 are recorded in the file structure/file area 10500 as shown in FIG. 14. In this example, the directory file is included in the FE (Dir-A) 10503.
In the VAT structure area 10520, a VAT 10521 to which the newly-recorded FE 10502, 10503, and 10504 are registered, and a VAT ICB 10522 are recorded.
When a close process is performed, first, predetermined data is recorded in the border-out area 10530 except for a next border marker 10531. Further, predetermined data is recorded in the physical format information area 10104 in the lead-in area 10101 which has remained unrecorded after the format process.
The close process is performed so as to allow the information reproduction apparatus to search for the latest volume file structure.
When such file recording process and close process is performed for the information recording medium 10100 having the data structure after the format process as shown in FIG. 13, the data structure as shown in FIG. 14 is formed in the information recording medium 10100.
Next, with reference to FIG. 15, a procedure for recording directory (Dir-B) and data file (File-b) of the file and directory structure shown in FIG. 12 will be described.
Herein, the data file (File-b) 10601 and the file structure related thereto, i.e., a file (File-b) 10601, a FE (File-b) 10602, a FE (Dir-B) 10603, and a FE (ROOT) 10604, are recorded in the file structure/file area 10600.
In a VAT structure area 106100, the latest VAT structure, i.e., a VAT 106101 and a VAT ICB 10602 are recorded.
At last, by performing the close process again, predetermined data is recorded in a border-out area 106200 except for a next border marker 106201. Further, the next border marker 10531 allocated in the border-out area 10530, and a border-in area 106300 including the physical format information area 106301 are recorded.
When such file recording process and close process are performed for the information recording medium 10100 having the data structure shown in FIG. 14, the data structure as shown in FIG. 15 is formed on the information recording medium 10100.
As described above, every time the close process performed, an area interposed between the lead-in area 10101 or the border-in area recorded in the volume space 10109 and the border-out area is formed. Hereinafter, such an area is called a bordered area. For example, in FIG. 15, there are bordered area #1 10700 and the bordered area #2 10701. The bordered area is a concept similar to a session in a CD-R disc.
Next, with reference to a flow chart for a reproduction process procedure shown in FIG. 16, a reproduction operation of a file will be described. Herein, an operation of reproducing the data file (File-a) 10501 will be described as an example.
First, data in the physical format information area 10104 in the lead-in area 10101 is reproduced, and the physical format information is obtained (step S11101).
Next, data of the next border marker is reproduced (step S11102).
The physical format information obtained in step S11101 (or step S11103) includes address information of the border-out area. Since the data of the next border marker is recorded at the predetermined position of the border-out area, the next border marker is reproduced from the position.
For example, in FIG. 15, the physical format information area 10104 includes address information of the border-out area 10530. Further, the physical format area 106301 included in the border-in area 106300 includes address information of the border-out area 106200.
When the next border marker included in physical format information obtained in step S1101 (or step S11103) has been already recorded, there is a newer bordered area. Thus, step S11103 and the following steps are performed.
In accordance with the address information of the border-in area included in the physical format information obtained in step S11101, reproduction of the next border-in area is performed (step S11103). The address information of the border-in area included in the physical format information can also be obtained in step S11104.
From the reproduced border-in area, the physical format information is obtained.
On the other hand, when the next border marker reproduced in step S11102 remains unrecorded, the current bordered area is the latest one. Thus, step S11104 and the following steps are performed.
When it reaches the latest bordered area, with reference to the latest obtained physical format information, an end physical address of the area which is accessible is obtained (step S11104).
In FIG. 15, the end of the bordered area #2 10701 is the end of the accessible area.
Then, at last, file reproduction is performed as follows.
At this time, the volume structure area 10410 is reproduced first (step S11105). The read out volume structure includes address information of file set descriptor 10421 and partition starting location. When the VAT method is employed, a virtual partition map defined by the UDF specification is included in the volume structure. Thus, based on the information, it is recognized that the VAT structure is recorded in the volume space.
The VAT ICB 106102 recorded at the end of the accessible area is reproduced (step S11106).
VAT recording position information is obtained from the read out VAT ICBP 106102, and the VAT 106101 is read out.
When a target file and/or management information thereof is managed using the virtual address, the VAT 106101 obtained in step S11106 is used for making reference to the VAT entry to which file entry of the target file and/or directory is registered (step S11107).
A translation process from the virtual address into the logical address is performed. Then, with having the file set descriptor 10421 in the file structure/file area 10420 as an origin, the FE (ROOT) 10604 in the file structure/file area 10600, ROOT directory recorded therein, the FE (Dir-A) 10503 in the file structure/file area 10500, directory (Dir-A) recorded in the FE, and the FE (File-a) 16502 are sequentially read out.
The recording position of the data file (File-a) 10501 is obtained from the FE (File-a) 10502, and the reproduction of the data file (File-a) 10501 is carried out.
A method for incremental recording to the DVD-R discs using the VAT method has been described above. However, the multiborder method is also known as an incremental recording method different from the VAT method. A similar method when used in the CD-R discs is called a multisession method.
In the multiborder method, data is incrementally recorded with having a bordered area as a unit, and the volume structure and the file structure are recorded for every bordered area.
In the multiborder method, a system of updating data using the virtual address such as VAT is not used. When the file structure is updated, the volume structure and the file structure are newly generated, and re-recorded in a new bordered area.
Reproduction using the multiborder method determines the latest bordered area, and reads out the latest volume structure therefrom.
Thereafter, a specific file can be reproduced by following data in accordance with the data structure defined by the UDF specification in steps. For example, data can be read out with a reproduction procedure similar to that for read-only discs like DVD-ROM.
Further, when the multiborder/multisession method is used, efficient data recording using the image data is performed. When all the files which are desired to be recorded are known, for example, when taking a backup of data, the data for all files which is desired to be recorded in a hard disc drive, and a file including all the volume structure and file structure thereof are produced. The file is image data. For recording the image data, one bordered area (or a session) is allocated, and the image data is continuously recorded in the area. Since recording is performed continuously, and the file structure has been already produced, overhead at recording becomes small. Thus, recording of the image data can be performed rapidly.
FIG. 33 is a block diagram showing a computer system 10200 and a drive apparatus 10300 disclosed in Japanese Patent No. 3005645.
The computer system 10200 includes a computer memory 10210 and temporary memory 10220, and transfer data to and from a write-once recording medium 10400. The temporary memory 10220 can transfer data to both a computer memory 10210 and the write-once recording medium 10400. The temporary memory 10220 includes a system file allocation area 10221, a medium directory area 10224, and a data file area 10225. The system file allocation area 10221 is an area for storing a file allocation table 10222, and an OS (operating system) directory 10225.
An operation of the computer system 10200 when recording a user file (user file including at least one of video data and audio data) in the write-once recording medium 10400 will be described.
FIG. 34 shows the data structure when the user file is recorded in the write-once recording medium 10400. In the file directory area 10510 of the write-once recording medium 10400, directory entry corresponding to the user file recorded in the file data area 10610 is recorded. The directory entry is a file structure in the write-once recording medium 10400, and includes the recording position on the write-once recording medium 10400 of the user file, file size, file name and the like.
An operation for recording a new user file in the write-once recording medium 10400 as shown in FIG. 34 will be described. Herein, the new user file is a user file generated by updating the user file recorded in the file data area 10610.
The computer system 10200 reads out all the directory entries from the write-once recording medium 10400, and stores in the medium directory area 10224. Then, the computer system 10200 exchanges the information of the directory entry in the medium directory area 10224, and forms the file allocation table 10222 and OS directory 10225 in the system file allocation area 10221. The file allocation table 10222 and the OS directory 10225 have the same structure as the file structure of a rewritable recording medium.
Next, the computer system 10200 transfers the new user file from the computer memory 10210 to the write-once recording medium 10400 via the data file area 10225. The new user file is recorded in, for example, a file data area 10620 shown in FIG. 35. In accordance with recording of the new user file, information in the system file allocation area 10221, i.e., the file allocation table 10222 and the OS directory 10225 are updated. In accordance with the update of the file allocation table 10222 and the OS directory 10225, the directory entry stored in the medium directory area 10224 is updated.
Finally, the updated directory entry is recorded in the write-once recording medium 10400. In FIG. 35, the updated directory entry is recorded in the file directory area 10520.
As described above, in the recording operation, the directory entry (file structure) on the write-once recording medium 10400 is read to the temporary memory 10220, and the directory entry is converted to a file structure similar to that of a rewritable recording medium. In accordance with the recording of the new user file, the file structure on the temporary memory 10220 is updated. The file structure of the rewritable recording medium is converted again into the file structure on the write-once recording medium 10400 and then is recorded on the write-once recording medium 10400.
In the reconversion process, all the directory entries are relocated from the file directory area 10510 to the file directory area 10520. For example, in FIG. 35, the directory entry 10511 is relocated in the directory entry 10521.
As shown in FIG. 35, the directory entry 10511 and the directory entry 10521 respectively have values such as ‘0’ to ‘C’ and ‘d’ to ‘g’ as logical address values. Modification to the logical address values is directly reflected in the conversion process performed in the temporary memory 10220. For example, the logical address for making reference to the directory entry 10512 is ‘b’. When the new user file is recorded, the logical value for making reference to the directory entry 10522 corresponding to the directory entry 10512 is ‘f’. Similarly, all the information related to the logical address in the file directory area can be modified.
For incrementally recording data in the write-once recording medium 10400, methods of reading out and converting the file structure such as directory information and/or location information recorded on the medium are widely used. This is because data cannot be recorded in the recorded area in the write-once recording medium. Further, since the conversion process of the file structure is required, the conversion process specific to the write-once medium should be performed when data is reproduced and recorded.
However, in the method as described-above, the reproduction operation of the directory or the file specific to the write-once recording medium is required. Thus, there is a problem in that a system which can only perform a reproduction operation of a read-only medium of rewritable recording medium cannot reproduce data in the write-once recording medium.
For example, for reproducing a user file recorded on a write-once recording medium such as DVD-R discs by the recording method as shown in Japanese Patent No. 3005645, the recording position of the latest file structure (for example, the file directory area 10520 in FIG. 35) should be known. In the recording method as shown in Japanese Patent No. 3005645, the position of the file directory area 10520 cannot be determined uniquely. Thus, some kind of method is required for figuring out the position. As such a method, for example, the multiborder/multisession method can be used.
Specifically, a first bordered area is set, and a file directory area 10510 and a file data area 10610 are provided in the first bordered area. Further, a second bordered area is set, and a file directory area 10520 and a file data area 10620 are provided in the second bordered area. The file directory area is provided at a predetermined position in the respective bordered areas (for example, at headers of the areas). When the reproduction operation is performed, the position of the latest bordered area is obtained by reading out the physical format information in the lead-in area or the border-in area in steps. Accordingly, even when the recording method shown in Japanese Patent No. 3005645 is used, it is possible to know the position of the latest file directory area if the multiborder/multisession method is used. However, this example still does not solve the problem that the system which does not support the multiborder (for example, read-only system) cannot read out the information.
In view of the above-described problem, the object of the present invention is to provide: an information recording medium which is compatible with a system which can only perform a reproduction operation for a read-only medium or a rewritable recording medium; a recording apparatus, a host apparatus, a drive apparatus and a recording method for recording information on the information recording media; a reproducing apparatus, a drive apparatus and a reproducing method for reproducing the information recorded on the information recording media; and a program which instructs the apparatuses to execute a recording operation and a reproduction operation.